﻿ Getting Started Tutorials - MechDesigner > Tutorial 5: Kinematic Function Blocks for Motion > Step 5.7: The Point-Data FB and Measurement FB

# Step 5.7: The Point-Data FB and Measurement FB

## Point-Data FB and Measurement Function-Blocks

The Point-Data FB and the Measurement FB have output-connectors only.

Use the Point-Data FB to measure the position of a Point.

Use the Measurement FB to measure a size of a sketch-element or the dimension between two sketch-elements.

The motion-values at their output-connectors includes the measurement AND its first and second motion-derivatives.

#### Motion-Dependency

This is an important concept. We can use these Function-Blocks in an importantThe motion of a kinematic-chain is dependent on a motion of a different kinematic-chain.

In the examples below (5.7-B and 5.7-C) there are TWO kinematic-chains, and ...

Kinematic-chain A : here a Crank. It uses a Linear-Motion FB , a copy of the MMA, as its motion and input to the Motion-Dimension FB, for the Crank.

We measure, with a Measurement FB, the distance between a stationary Point in the Base-Part and the end-Point of the Crank. The distance continually changes as we cycle the model.

The output from the Measurement FB provides not only the distance between the two Points, but also the first and second motion-derivatives of the distance between the two Points.

Kinematic-chain B: here a Slider. It takes the motion-values at the output from the Measurement FB as its motion and input to the Motion-Dimension FB, for the Slider.

 Terminology: Motion-Dependency We say that Kinematic-Chain B has Motion-Dependency on Kinematic-Chain A 5.7-A: Plot Motion-Values with a Graph FB 5.7-B: Use motion-values at the input to a Motion-Dimension FB for a different Kinematic-Chain 5.7-C: Motion-Values at the input to a Motion FB and Motion-Dimension FB from a different Kinematic-Chain Develop a Stationary Cam